ANDROID: drivers/arm-smmu-v3-kvm: Free io_pgtable struct on domain free

When a domain is freed, it should also free the page table struct
"arm_lpae_io_pgtable" which is per domain, as the domain is freed
and this memory would be leaked.

Bug: 277989609
Bug: 278749606

Change-Id: I6eaf00977d613d203f3918485d4cd8618ec40c9e
Signed-off-by: Mostafa Saleh <smostafa@google.com>